Retted bagasse fiber and process of producing same



I closed and Patented June 28, 1927.

UNITED STATES PATENT OFFICE.

ELBERT C. LATHROP, OF PHILADELPHIA, PENNSYLVANIA, AND TREADWAY MUN- ROE, OF FOREST GLEN, MARYLAND,

ASSIGNORS, BY DIRECT AND MESNE ASSIGN- MENTS, TO DAHLBERG &'COMPANY, IN 0., OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

RETTED BAGASSE FIBER AND PROCESS OF PRODUCING SAME.

No Drawing.

j This invention relates to retted bagasse fibers and process of producing the same, and has for its object to improve the fibers heretofore produced from bagasse,.while at the same time preserving said fibers from deterioration, in a manner more simple and less costly than has been heretofore proposed.

. With these and other objects in view, the invention consists in the novel retted ba gasse fiber and in the novel steps and combinations of steps constituting the process, all as will be morefully hereinafter -disparticularly pointed out in the claims.

In order that the precise invention may be the more clearly understood, it is said In the manufacture of heat insulating and building boards or lumber from bagasse and analogous.-.fibers, it is desirable to separate the fiber bundles more or less completely into single fibers, and this has been heretofore attempted by cooking the fibers either in Water or in alkaline, or in acid solutions. After said fibers are thus cooked they are subjected to a washing action and then to the mechanical working of the fibers in beaters called Jordan engines, or in Claflin refiners, so that the fiber bundles are more or less broken up, and single fibers or smaller fiber bundles are formed from the larger bundles.

This mechanical treatment, however, is more or less costly, and furthermore it is carried out imperfectly in the machinery nowemployed, due to the strong cementing action of the parenchyma tissue and pith which bind the single bagasse fibers into fiber bundles. sue should be removed entirely by the cook 111g processes if strong chemicals are em- While this parenchyma tis Application filed June 20, 1924. Serial No. 721,366.

may be brought about in such a way that but little, if any, cooking and mechanical refining is required. It thus results that when this invention is followed, a less loss of valuable fiber constitutents is involved than by the now commonly practiced chemical cooking processes. Furthermore, the pulp manufactured from such retted bagasse 'bers possesses certain properties not attained by the pulp that has been heretofore manufactured, as will presently appear.

- Inorder to still further make clear the precise nature of this invention, it is also said 'Bagasse fibers as they leave the sugar cane mill contain about 50 per cent moisture and varying but small amounts of unextracted sugar, depending on the particular mill operations to which they'have been subjected. It is well known that such bagasse can be immediately dried and by this means all fermentation changes can be prevented, since it is well known that microorganisms. require water in order to grow and carry on their processes of metabolism commonly called fermentation. But, again, such drying procedure is found to be too and the resulting bagasse fiber is in addition .found to be harsh, and the individual fibers themselves are found to be held for the most part in the form of firm bundles due to the above-mentioned parenchyma tissue and therefore they must be subjected to cooking and refining procedures before they can be made into a satisfactory pulp.

On the other hand, if the green masses of bagasse are piled either loose or in bales, as they come from the mill with the varying Water contents they possess, fermentation as is well known sets in. It therefore follows that if one simply piles a mass of bagasse as it comes from the mill,'the growth of certain groups or types of bacteria, fungi or mushrooms, is favored or inhibited, depending upon the chance conditions of the particular temperature, the particular moisture content, the oxygen supply, or the hydrogen ion concentration with which the mass may have been associated. Itthus results that the particular type of fermentation, and therefore of final product, is very uncertain, for each may be quite different in different masses that, have been treated alike, and

' have been studied .tion, and it has been found that these mush-e.

found bacteria, trichoderma, monilla,

also the amount of heat produced in the different masses will varyaccording to said chance conditions. 7 v

Of these organisms, there have been Fusarium, Aspergillus, Penicillum, Mucors, and various species of mushrooms to be present under various conditions, but in studying the effect of the organisms on bagasse fiber, both in the case of 'pure and in the case of mixed cultures, it has been discovered that certain of the organisms are quite selective in their attack on bagasse constituents. In particular, it has been discovered that the mushrooms are selective in their fermenta= tion changes under controlled conditions. Certain types of mushrooms in pure cultures on bagasse, and in bales of bagasse, in the field as to their ac-' rooms attack the parenchyma tissue in pref- Masses of bagasse,

erence'to the bagasse fiber so that this said completely destroyed,

-touched.

which have been so fermented, are of a yellowish color, and

' when'such masses are rubbed between the hands, the individual fibers are partially or wholly separated from the fiber bundles, so that the mass seems much softer'and more pliable than was the bagassev before such fermentation or retting. Studies on the diameters of fibers produced by such mushroom retting as compared with the unretted bagasse fibers which have been treated by the prior cooking and refining procedures have shown that on the average the retted fibers are of a satisfactory uniform character and quality, are of a smaller diameter and that they show a larger proportion of single fibers produced by the retting process than have been heretofore produced by the cooking and refining processes. It has also been found that' a number of species of mushrooms will produce the desired retting action, such forexample as Hypholm'a, A aricus, Copr'inus, Cortilfarius or Psilocy e, It has been discovered that the Psilocybe species may be easily grownin a pure cul ture, and while one may carry out this invention by the use of other species, one way in which to perform this process is by the use of the said Psilocybe, mushrooms.

Psilocybe and similar mushrooms are found to grow best on bagasse at a moisture content above 60 per cent and at temperatures normal to cane growing countries. The conditions of oxygen supply and hydro en ion concentrations are also found to be lmportant. That is, it is found that Psilocybe grows well at a hydrogen ion concentration (pH) of 4.0 to 5.5, and that it develops rapidly in compacted masses of bagasse such as are produced by baling in fiber practically unthe well known manner described in U. S. Patent No. 1,479,419, for Method of preserving bagasse fibers, etc., dated January 1, 1924, and issued to T. B. Munroe. But in this invention no alkali or other chemical is added to the bagasse previous to the baling of thesame or during the process of retting said bagasse.

As is well known, the green bagasse as it leaves the mill, and when ei'ther'in loose piles or in bales, at first undergoes an alcoholic and then an acetic or other acid fermentation. It has been found if water is not then supplied to the bagasse above approximately 50 per cent, the bales will heat up under this fermentation and may be substantially sterilized by the heat thus generated. In order to ret the bagasse, however, by this invention, the moisture content of the bagasse in which the cultures are started should be raised above 60 per cent topr'eferably from per cent to 80 per cent,'although a higher moisture content is not objectionable.

The cane growing soils in general are found to have in them growing mushrooms,

or spores of mushrooms, and therefore the cane is alreadyinoculated with certain species of mushrooms when the bagasse is made at the mill. Especially is it found that the cane growing soils of the Southern States contain the species of mushrooms known as Psilocybe.

by the conditions of moisture and tempera time above noted, and in carrying out the present invention, one brings about those conditions which will induce an optimum growth of the desired species of mushroom. That is, in those cases where the cane itself is not sufficiently inoculated with mushroom fruiting bodies, ing out this invention inoculate the bagasse itself, either while it is being baled, or later, by using soil that is inoculated with the desired species of mushroom or other cultures, such for example, as Psilocybe. In carrying out this inoculation, one may also employ previously retted baled bagasse or he may use pure cultures of Psilocybe, especially grown in suitable and well known media.

It has further been found that it is not necessary to inoculate or start the growth of mushrooms in all of the bales of a pile of bagasse, or even in \all parts of a mass of loose bagasse. .It is found sufficient if the outer bales of a pile of bagasse are well inoculated for good growths of the Psiloare induced by the control of the IDOlS- It is also found that the growth of the mushroom will be favored d or spores, one may in carry struction of the pith and parenchyma tissue is likewise controlled; therefore by controlling the moisture present the tendency for the organism to attack the true fiber is substantially eliminated. It is further found that sterilized bagasse, after it has cooled down sufliciently, is one of the most suitable forms in which to produce the retted bagasse. That is the Psilocybe is about the only type that will grow in such sterilized bales for the conditions for growth of other organisms have been made unfavorable by the process of sterilization.

It is still further found that when piles of bagasse which have been retted are opened up, it is observed that the bales on the inside of the piles appear as whitish bales on their outsides, the interior of such bales bein'g yellow and the bales themselves being substantially dry. But the fiber of such interior bales is found to bestrong and some of the pith and parenchyma tissue will have been found to be destroyed, so that on'mechanical rubbing, such a shredding of the fibers takes place that they will fall apart, there being present a larger proportion of single fibers or small fiber bundles than have been found in bagasse not so retted. I I

Although it is to be understood that the invention may be carried out in other ways without departing from the spiritthereof, one manner in which it may be performed isas follows:-

The bagasse is b aled in 'a compacted mass such as that described in U. S. Patent No. 1,479,419, above mentioned, with the exception that no lime or other chemical is added to the bagasse as it leaves the sugar mill prior to baling. About 50 per cent of moisture remains in the bagasse after baling and the bale is so compacted that very little heat escapes therefrom.

' During the .control of fermentation of this material, or within the course of a day to a few days, the alcoholic and lower fatty acid fermentation will begin, at which time a pro duction of carbon dioxide begins and the bales heat up. The bales are preferably then laid into piles of several hundred or thousands of bales to a pile, so that the proportion of bales exposed to the direct weather is small as compared with the baes not so exposed. The bales are'so placed in the piles that air channels are formed within the pile, both laterally and vertically. The purpose of these air channels is to. supply air currents to remove the vapors and gases from the bales, during the pasteurization process, and to supply oxygen so as to limit the rowth of certain types of organisms which are effective in producing other conditions of fermentation than those producing the pasteurizing effect. If the bales are too closely packed in piles, carbonizing and scorching of the fibers is apt to take place. If disposed-in small piles, or with exceedingly large air channels the heating may be of too short a duration to pasteurize and sterilizethe mass. During storage, under the above conditions, a substantial sterilization takes place and the moisture content of the whole bale is markedly lowered, but particularly the outside of the bales are dried out so that at touch and sight the bales appear entirely dry. If kept dry, substantially no furtherfermentation takes place, for the heating up and drying out process will have destroyed the microorganisms which bring about the effective fermentation process.

Instead of covering the bales with loose bagasse at the time of piling, the bales may be piled without any cover. In so doing, the heat is morequickly removed from the interior of the pile, permitting the desired temperature conditions for retting to become favorable at an earlier period. The moisture that is condensed on the under sides of the top bales, is found to supply the high moisture conditions necessary for the beginning of the germination and growth of the mushroom: In about three to six weeks, if the mushroom growth by such condensation of vapor is not sufficiently well started, the outer bales should be wetted in a suitable manner, and if desirable they may be also wetted with a mixture of mushroom myselium and micro-spores in a suitable dilutent such as a media or water. The acid condition produced by fermentation in this process causes the mushrooms to start their growth and penetrate from bale to bale. so

that in a period of a month to several months the entire mass of bagasse is substantially retted. In order to protect the bales of a pile, from secondary ferm'entations such as that produced by slime molds after such time as the mushroom organisms have penetrated well into the pile, the top bales of the pile are broken and spread over the other bales as loose bagasse to form a layer approximately eight inches in depth, a small amount of venting being provided to carry off the carbon dioxide vapors produced during the retting.

It will now be clear that this invention provides a procedure by which one may pile green bagasse from the mill either in masses or in bales, allow it to go through an alcoholic fermentation, and so regulate the temperature thus generated throughout the-mass as to substantially pasteurize, the same without injury to the fibers. After this pasteur- Psilocybe.

all cases the raw -ing material for the ization by heat has been accomplished, one then examines the mass to find if it still is inoculated with organisms of the mushroom type and especially of the type of If this mushroom type of fermenting organism is not present in sufiicient quantities, the bagasse masses are then suitably inoculated therewith, and the bagasse left to the action of said growths. The mass if too dry should be moistened in order to start the mushroom fermentation or retting action, and a moisture content above 60 per cent should be supplied and maintained.

After" the retting action is once started, however, the mushroom organisms will by their fermenting action supply additional moisture so that the retting action spreads rapidly throughout the mass, no matter how large it may be. These mushroom types of organisms are found. to attack the parenchyma tissues binding the fibers together in bundles, and they thus loosen said fibers, rendering it unnecessary to subsequently cook and mechanically beat the same to the extent heretofore foundnecessary with unretted fibers during pulp making processes. Further, by controlling the temperature and the moisture content, the retting action of the organisms can also be controlled and the fibers recovered with their strength and flexibility unimpaired.

The retted fibers themselves are found to be of a yellow color, more pliable, and of a smaller diameter than those produced by the prior cooking and refining procedures.

It will further be clear that instead of sterilizin the bagasse as above disclosed, it may e inoculated, with a number of different mushroom types of organisms and retted with improved results. Y

It will also be clear that this invention is not limited to bagasse fibers, for analogous fiber producing materials such as bamboo,

cornstalks, rice straw, and even wood, may be similarly treated to advantage. For in fibers through this retting action are so separated from the which consists in subjecting said material to' the fermenting action of micro-organisms of the mushroom type.

2. The process of preparing fiber produc roduction of pulp which consists in acidi ying said material by subjecting the same to an alcoholic and acid'fermentation and then to the fermenting action of micro-organisms of the mushroom type. i v

'3. The processof pre aring fiber producing material for the su sequent production range of'temperature to the ermenting acterial in bundles in which they are bound by nature,-that.it

of pulp which consists 'in subjecting said material in the presence of a predetermined water content to the fermenting action of micro-organisms of the mushroom type.

4-. The .process of preparing fiber producing material for the subsequent production of' pulp which consists in subjecting said material in the presence water content and within a redetermined tion of micro-organisms type.

5. The processof preparing fiber producing material for the subsequent production of pulp which consists in subjecting said mathe presence of a predetermined water content and within a predetermined temperature range first to "an alcoholic fermentation and then to the fermenting action of -the mushroom v of micro-organisms of the mushroom type.

of a predetermined 6. The process of preparing fiber pro ducing material for the subsequent production of pulp which consists in subjecting said material to an alcoholic fermentation; bringing said fermented material to a predetermined range of temperature and to a I predetermined moisture. content and subjecting the same to the fermenting action of a micro-organism of the mushroom type.

7 The process of preparing fiber producing material for the subsequent production of pulp which consists in subjecting said material to an alcoholic fermentation; so controlling the temperature of said material during said fermentation as to partially sterilize the same; bringing saidfermented material to a predetermined range of temperature and to a predetermined moisture content and subjecting the same to the fermenting action of a micro-organismof the mushroom type. I

8. The process of preparing fiber producing material for the subsequent production of ulp which consists in subjecting s aid material to an alcoholic fermentation; causing the heat developed by said fermentation to sterilize said material to' a substantial extent; bringing said fermented material to a predetermined range of temperature and to apredetermined moisture content 1 and subjecting the same to the fermenting action of a micro-organism of the mushroom type known as psllocybe.

9. The process of preparing fiber produc-' 'ing bagasse material for the production of v pulp which consists in subjecting said .ma-

terial to .the fermenting action of microorganisms of 'the mushroom type.

3-10., The process of preparing fiber producing bagas"e material for the subsequent production of pulp which consists'in subjecting said materihl in the. presence of a predetermined water content to the fermenting action of micro-organisms of the'mus room type.

ecting said material to an alcoholic fermentation; bringing said fermented material to a predetermined range of temperature and to a predetermined moisture content and subjecting the same to the ferment ing action of a micro-organism of the mush room type.

12. The process of retting bagasse fibers which consists in subjecting a mass of bagasse to an alcoholic fermentation; causing its water content to exceed 60%; and subjecting said mass to the fermenting action of a micro-organism of the mushroom type.

13. The process of retting bagasse fibers which consists in subjecting a mass of bagasse to an alcoholic fermentation; causing the heat generated to, sterilize said mass to .a substantial extent; causing its water con-- tent to exceed 60%; and subjecting said mass to the fermenting action of a microorganism of the mushroomvtype.

"14. The process of re'tting bagasse fibers which consists in subjecting a mass of bagasse to an alcoholic fermentation; causing its water content to exceed 60%; and subjectingsaid mass to the fermenting action of a micro-organism of the mushroom type known as psilocybe.

15. The process of preparing bagasse fibers for pulp making purposes; which consists in subjecting a mass of bagasse to an alcoholic fermentation; and then to a fermentationbrought about by micro-organisms of the mushroom type under predetermined controlled conditions of temperature, water content and oxygen supply.

16. The process of preparing bagasse fibers for pulp making purposes, which consists insubjecting a mass of bagasse to an alcoholic fermentation; and then to a fermentation brought about by micro-organisms of the mushroom type known as psilocybe under predetermined controlled conditions of tiimperature, water content and oxygen supy. 17. The process of preparing bagasse fibers for pulp making purposes, which consists in sub'ecting a mass of bagasse to an alcoholic ermentation; substantially sterilizing said mass; and then subjecting said massto a fermentation brou ht about by microorganisms of the mus room type known as psilocybe under predetermined controlled conditions of temperature, water content and oxygen supply.

18. The herein described new article of manufacture consisting of a mass of bagasse fibers yellow in color, pliable, of a less average diameter than those ordinarily produced by cooking and beating procedures, and produced by the retting action of microorganisms of the mushroom tygg.

In testimony whereof we a our signatures.

ELBERT C. LATHROP. TREADWAY B. MUNROE. 

